“…The disease is characterized by mesangial deposition of polymeric IgA1 (pIgA1), proliferation of mesangial cells, increased synthesis of extracellular matrix, and infiltration by macrophages, monocytes, and T cells (2). Immunoregulatory abnormalities involving IgA1 synthesis in IgAN include overproduction of IgA1 by B lymphocytes in vitro (3,4), increased serum levels of IgA, IgA-containing immune complexes (5,6), and anionic IgA (7), and abnormal glycosylation of the carbohydrate moieties in IgA1 from these patients (8). Five different IgA receptors have been identified in human subjects, including Fc␣R1 or CD89, the polymeric Ig receptor, the asialoglycoprotein receptor, Fc␣/ R, and the transferrin receptor or CD71.…”